Arithmetic Ability
Time and Work

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Q.

A is 30% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 23 days ?

View Answer

Correct choice: C

Explanation:

Ratio of times taken by A and B = 100 : 130 = 10 : 13. Suppose B takes x days to do the work. Then, 10 : 13 :: 23 : x => x = ( 23 x 13/10 ) => x = 299 /10. A's 1 day's work = 1/23 ; B's 1 day's work = 10/299 . (A + B)'s 1 day's work = ( 1/23 + 10/299 ) = 23/299 = 113 . Therefore, A and B together can complete the work in 13 days.
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